Vapor to liquid heat exchanger



Nov. 8, 1955 A. KlRKPATRlcK VAPOR To LIQUID HEAT EXCHANGER 2Sheets-Sheet l INVENTOR. ALTON KIRKPATRICK d 21W 3 @3 Z mm/ G w H m. amMa W W E L f /v l a |f d M67/ Z ,aw In HW in l Enr/Ill l -IIMHM I II|| lI I I IIIFLMI.. .n. y m... a ulllll/ .|...I|: I. W 3m /O l I l Inl? 5www, QNJ l O 9,1/ E r Q A V m Z 7 m w W e .l M n N Nov. 8, 1955 A.KIRKPATRICK VAPOR To LIQUID HEAT EXCHANGER 2 Sheets-Sheer?l 2 Filed Jan.29, 1955 g@ @O0 OOO@ @@@GQ Q @@@OG O @0090 009090 /f 7 ff@- FIG2.

IN VEN TOR. ALTON KI RKPATRICK BY M1/40M,

atent Oice Patented Nov, 8, 1955 VAPOR TO LIQUID HEAT EXCHANGER AltonKirkpatrick, Brighton, Mass., assigner to Stone &

Webster Engineering Corporation, Boston, Mass., a corporation ofMassachusetts Application January 29, 1953, Serial No. 333,980

4 Claims. (Cl. 257-32) This invention relates to vapor to liquid heatexchangers and especially to vertical tubular vapor to liquid heaterswhich are adapted to sub-cool the condensate.

Speaking generally, the invention provides adequate sub-cooling withpositive and continuous removal of the condensate to another vesselduring continuous operation of the heat exchanger. Positive andcontinuous condensate discharge is attained despite a minimum ofpressure differential between the vapor pressure of the heat exchangerand the pressure of the succeeding vessel.

Briey, this is accomplished by employment of a vertical partition memberdisposed wthin the outer shell of the heat exchanger, the partitionbeing xedly mounted in a fluidtight manner and extending upwardly fromthe bottom of the outer shell to a point short of the top thereof todivide the outer shell into a condensing chamber and a sub-coolingreservoir. Conventional cooling tubes extend into both chambers andcooling water is circulated therein. A pump feeds collected condensatefrom the condensing chamber into the sub-cooling chamber and aregulatable outlet is provided through the outer shell from thesub-cooler to discharge the condensate, the capacity of the pump beinggreater than the vapor condensing capacity of the heater.

Preferably, a sub-partition is vertically disposed within the sub-coolerand is fixedly mounted therein in a fluidtight manner, the sub-partitionextending from the bottom to a point short of the top of the sub-coolerto divide the latter into two passes. With this preferred arrangement,the pump is connected to one pass and the outlet leads from the otherpass.

More preferably, level control means responsive to changes from apredetermined level of condensate with'- in the condensing chamber is orare provided and suitably connected to the regulatable outlet tomaintain the sub-cooler flooded and a desired condensate level in thecondensing chamber.

The accompanying drawings, referred to herein and constituting a parthereof, illustrate a preferred embodiment of the invention, and togetherwith the description, serve to explain the principles of the invention.

Of the drawings: l

Fig. 1 is a front elevation of a preferred embodiment of the invention,partly in section to reveal the internal structure.

Fig. 2 is a section along the line II-II of Fig. 1.

Fig. 3 is a side elevation of the heat exchanger of Fig. l, partly insection to reveal the internal structure.

Referring now in detail to the illustrative embodiment of the inventionshown by way of example in the drawings, a headdown feed water heater ismounted on support legs 1. lt has a vertically disposed outer shell 2encasing a conventional floating-head type bundle of cooling tubes 3rising from the fixed tube sheet 3a of partitioned header 3b.Advantageously and as here preferably embodied, the shell 2 is oftwo-part construction comprising a fixed lower portion or shell collar2a sealingly attached to the tube sheet 3a, and a removable upperportion 2b bolted to the shell collar. Cooling water supply andcirculation Within the tubes is provided by header inlet 4, and headeroutlet 5, and suitable driving means such as a pump, etc. (not shown).

A tubular partition 6 is vertically disposed within outer shell 2. It isfxedly mounted at its bottom end in sealing engagement (iluidtightmanner) with the fixed tube sheet 3a and the inner surface of shellcollar 2a. It extends upwardly to a point 6a, short of the top of outershell 2, thus forming a reservoir for sub-cooling condensate, i. e., asub-cooler chamber, and, in effect, dividing outer shell 2 into acondensing chamber 7 and a subcooling chamber 8, the latter being openat the top. In the preferred embodiment illustrated, the partition 6 hastwo plane-surfaced sides at right angles to each other' connected by athird curved side of a contour matching that of the shell. The curvedside terminates short of the other two sides and is provided with aradially extending flange 6b which is welded to the fixed shell collar2a.

A sub-partition 9 is vertically disposed within the subcooler chamber 8and is fixedly mounted therein in sealing engagement therewith(fiuidtight manner) extending from the bottom to a point 9a short of thetop of subcooler 8. Thus, sub-partition 9 divides the sub-cooler into afirst pass 10 and second pass 11.

Outer shell 2 has an inlet 12 for vapor leading into condensing chamber7, and a condensate outlet 13 leads from the second pass 11 to dischargecondensate into the next succeeding vessel, e. g., another heatexchanger but of lower pressure. A valve 13a regulates ow through theoutlet 13.

A pump 14 is connected by suction chamber unit 15 to the lower portionor condensate collecting portion of the condensing chamber 7, and is"connected by pipe 16 to the lower end of the first pass 10, to removecondensate from the condensing chamber 7 and force it into thesubcooling chamber 8 (the first pass 10, as shown). The pump 14 has agreater fluid moving capacity than the steam condensing capacity of theheater.

A float level control 17 responsive to changes in condensate levelwithin the condensing chamber 7 is suitably connected thereto and to theValve 13a to regulate the valve opening and maintain the condensatelevel at about the level indicated as 13. Drain plugs 13b and 15a in theshell collar 2a and the suction chamber unit 15 permit of drainage ofthe sub-cooling chamber 8 and the condensing chamber 7.

Operation of the preferred feed water heater illustrated is as follows:Steam enters the condensing chamber 7 and sub-cooler 8 through the inlet12 and is condensed on the cooling tubes 3 in each chamber. Condensatecollects in the lower portion of sub-cooling chamber S and also ofcondensing chamber 7 from which latter it is drawn by pump 14 throughpipe 15 and forced via pipe16 into the first pass 10 of sub-cooler 8. Asthe operation continues, more and more condensate is collected incondensing chamber 7 and is forced into the first pass 10 of thesub-cooler by pump 14 until the condensate level therein rises to thetop 9a of the partition or weir 9. As the operation continues,condensate spills into the second pass 11l over weir 9 from the firstpass and counterows by gravity down the second pass, the condensatelevel rising rapidly in the second pass, Valve 13a being closed. Whenboth passes are full of condensate, the pump continuing its forcing ofcondensate into the bottom of the iirst pass, causes the condensate tospill over the top 6a of the baffle 6 and flood into the condensingchamber 7, collecting at the bottom thereof, where it is recirculated bythe pump. The condensate level at the bottom of condensing chamber 7begins to rise considerably at this point of the operation, and when itrises to level 18, float level control 17 actuates valve 13a to openoutlet 13 and circulatedsub-cooled condensate discharges from the secondpass 11. Float level control 17 opens valve 13a enough to permit removalof condensate at a rate suflicient to maintain` the predetermined levelof condensate in condensing chamber 7. As the operationcontinues,entering vapor isv continuously condensed and condensate in the condensing chamber 7 pumped into sub-cooler 8. The subcooler is maintainedin a flooding condition so that condensate is rst sub-cooled by passageup the first pass 10 and then spilled into the second'pass 11 foradditional sub-cooling, from whence it eventually is discharged to thenext succeeding vessel via pipe 13.

With this arrangement, the circulating condensate issubstantiallyvsub-cooled prior to discharge to the next succeedingvessel. In addition, a static head of suiiicient pressure is maintainedin the second pass of the subcooler at all times so that discharge ofthe condensate through outlet 13 to the next succeeding heat exchangero1' vessel can be accomplished continuously and simply at all times,even though the pressure differential between the instant heat exchangerand the one next succeeding be at minimum values.

The capacity of the recirculating pump is in excess of the totalcondensing capacity of the heater, thus maintaining the sub-coolersection ooded at all times, any surplus overflowing the sub-coolersection to the level controlled condensate storage volume at the bottomof the heater.

Although it is not preferred, the invention may be utilized without theuse of sub-partition 9. However, for optimum circulation andsub-cooling, I prefer the form of the invention described. Because ofthe provision of the two-part shell 2 with a flanged joint between thefixed lower part 2a and the removable upper part 2b at a suitabledistance above the lixed tube sheet 3a, the recirculating pump andcondensate drain connection can be brought out below this ange and neednot be broken in order to remove the heater shell.

In the type of heater described, if the recirculating pump fails, theheater will operate as a conventional heater.

It will be understood that the invention is not limited to the detailsdescribed and shown in the drawings, except as appears hereafter in theclaims.

What is claimed is:

l. A vapor to liquid heat exchanger comprising a vertically disposedshell; a vertical partition member lixedly mounted in fluidtight mannerwithin said shell and extending from the bottom thereof to a point shortof the top thereof to divide said shell into a sub-cooling chamber openat the top, and a condensing chamber; cooling tubes within both of saidchambers; means for supplying and circulating cooling iiuid through saidtubes, an inlet in said shell to supply condensible vapor to saidcondensing chamber; a pump connected to the said condensing chamber andsaid sub-cooling chamber to circulate collected condensate from thecondensing chamber to said sub-cooling chamber, the capacity of the pumpbeing greater than the total condensing capacity of the heat exchanger;and, an outlet from said sub-cooling charnber to remove condensate.

2. The subject matter of claim 1 including a subpartition member iixedlymounted in uid-tight manner within said sub-cooling chamber andextending from the bottom thereof to a point short of the top thereof todivide it into a first pass and second pass, and characterized by thefact that said condensate outlet leads from one of said passes and thepump is connected to the other of said passes.

3. A vapor to liquid heat exchanger comprising a vertically disposedshell; a vertical partition member iixedly mounted in huid-tight mannerwithin said shell and extending from the bottom thereof to a point shortof the top thereof to divide said shell into a sub-cooling chamber openat the top, and a condensing chamber; a sub-partition iixedly mounted iniiuid-tight manner within said sub-cooling chamber and extending fromthe bottom thereof to a point short of the top thereof to divide saisub-cooling chamber into a iirst pass and a second pass` cooling tubeswithin said condensing chamber and sai sub-cooling chamber; means forsupplying and circulating cooling fluid through said tubes; an inlet tosupply condensible vapor to said condensing chamber; a circulating pumpconnected between the bottom portions of said condensing chamber and thefirst pass to circulate collected condensate from the condensing chamberinto said irst pass, the capacity of the pump being greater than thetotal condensing capacity of the heat exchanger; an outlet from saidsecond pass to remove condensate; adjusting means on said outlet to varythe rate of ow therethrough; and, level-controlled means connected tosaid condenesing chamber responsive to changes in the level of collectedcondensate in said condensing chamber to regulate said adjusting meansto maintain a pre-determined level in said condensing chamber.

4. A vertical tubular heater including a fixed tube sheet and comprisinga two-part vertically disposed shell, one of said parts being a ringlixed to the lixed tube sheet of said heater and the other being open atone end and closed at its other end and removably connected at its openend to said ring part; a vertical partition member ixedly mounted inuid-tight manner within said shell to said tube sheet and to said fixedring part and extending from said tube sheet to a point short of theclosed end of said removable shell part to divide said shell into asub-cooling chamber open at the top, and a condensing chamber; coolingtubes within said chambers; an inlet to supply condensible Vapor to saidcondensing chamber; pumping means connected to said ring part betweensaid condensing chamber and said sub-cooling chamber for circulatingcondensate from said condensing chamber to said sub-cooling chamber, thecapacity of said pump being greater than the total condensing capacityof the heater, an outlet in said shell ring for removing condensate fromsaid sub-cooling chamber; adjusting means on said outlet for varying therate of flow therethrough; and, levelcontrolled means connected to saidcondensing chamber responsive to changes in the level of collectedcondensate in said condensing chamber to regulate said adjusting meansto maintain a predetermined liquid level in said condensing chamber.

References Cited in the iile of this patent UNITED STATES PATENTS

